Since the protocol was approved in 2009, we have evaluated 15 prospective patients and 9 patients have agreed to participate in the renal function study component of the sickle cell protocol. One of the nine patients has been lost to follow-up following the initial visit. Eight patients have completed one year of the study; however, no patient has agreed to undergo repeat iothalamate measurement of the glomerular filtration rate. Many also have either refused or otherwise failed to undergo repeat water deprivation test at 12 months despite repeated attempts by the coordinator. Moreover, many patients are failing to follow through with designated follow-up blood draws or 24-urine collections. Creating the addendum for remuneration of the procedures has not improved the compliance of the patients to adhere to the protocol. Because of the difficulty obtaining data over the course of the 12 months following bone marrow transplant in this patient population, I have decided to forgo accepting further patients into this protocol. The last patient who was enrolled in the protocol has recently undergone the final follow-up studies. We will perform the data analysis in the near future.